The invention is directed to a capacitor, particularly a dry capacitor, which can be made from metallized plastic films or a plastic film and metallic foils as the plates, with an external protection provided by a shrinkable tube.
Capacitors are electronic components, used in electro-electronic devices. The capacitor comprises a capacitive element, which is formed by two plates or films and one dielectric, which are either wound or stacked. The capacitive element is connected to elements of an electrical circuit by terminals. With an electrical current applied to these terminals, the capacitor is loaded with an electrical load.
There are a lot of different types of capacitors: film capacitors (polyester or polypropylene), ceramic, electrolytic, tantalum, etc. This invention is applicable to any of these types, which may be a dry capacitor (without a presence of a liquid substance in its composition) that needs a cover to provide a mechanical and/or electrical protection.
The capacitors normally need an external cover in order to be handled without mechanical damages during the assembling in the circuit. This cover has the function to protect the capacitor and the neighbor components from short circuits, which could damage the whole circuit, to assure the mechanical robustness to the capacitors during the handling and to assure the attachment of the terminals during a soldering process.
There are known capacitors in a naked version (without protection cover), which are boxed in plastic cans and covered by epoxy powder resin.
Most of the plastic capacitors are covered by one of the processes mentioned above. The naked version has application in some restricted fields, because it is sensitive to mechanical agents and soldering processes.
The covering techniques provide the capacitors with the necessary protection against external mechanical agents, as well as from a contact with the neighbor components, to avoid short circuits.
The object of the invention is to provide a capacitor with one protection system against mechanical and electrical external agents, in a simple and cheap manner, by avoiding the use of the known plastic can and by using a shrinkable tube, which is shrunk directly on the capacitive element.
The objective is reached using a capacitor, particularly a dry capacitor, formed by a capacitive element, contact terminals and the capacitive element has a thermo shrinkable plastic tube, which is applied directly on the capacitive element.
The invention is also directed to a capacitor manufacturing method using a thermo shrinkable material which is applied directly on the capacitive element without using the well-known plastic can. Thus, the method makes the production cheaper.
The objective is reached using a manufacturing method, particularly a dry capacitor manufacturing method, by providing the capacitor formed by a capacitive element and contact terminals, applying a thermo shrinkable tube directly on the capacitive element and then heating to shrink the thermo shrinkable tube onto the capacitive element.